To preserve proper drainage of water, culverts are frequently installed through any road or other embankment which otherwise interferes with the natural drainage of the land. In areas where beavers are active, however, the inlet side of such a culvert provides a desirable location for beavers to construct a dam. Culverts usually are of a relatively smaller cross-section than the ditch or waterway, and are therefore relatively easy for beavers to completely obstruct. Not only will beavers build dams across the openings of such culverts, but frequently they will carry their workings into the culverts as well.
For a variety of environmental and economic reasons, beaver dams must be cleared from culverts to allow proper water drainage. Failure to remove dams can cause localized flooding and inhibits or interferes with established land uses. Removal of dams is labor-intensive and costly, however. It is often difficult and/or expensive to utilize construction equipment (such as a backhoe), and manual methods are understandably undesirable. Furthermore, if beavers have built a dam into the culvert, it can be removed only by hand, painstakingly, or by expensive horizontal boring equipment. In some instances the only solution is to actually replace the entire culvert, an extremely expensive and undesirable solution. This situation is compounded by the industriousness of beavers; it is not uncommon for beavers to entirely obstruct a given culvert within 24 to 48 hours after it has been cleared by a crew of workmen.
Past efforts at remedying this problem have frequently been directed toward trapping or otherwise controlling the beavers themselves. These solutions are not entirely effective, and are offensive to certain segments of society.